Cannabinoid treatment for autism: a proof-of-concept randomized trial

Abstract

Background: Endocannabinoid dysfunction in animal models of autism spectrum disorder (ASD) and accumulating, albeit anecdotal, evidence for efficacy in humans motivated this placebo-controlled double-blind comparison of two oral cannabinoid solutions in 150 participants (age 5-21 years) with ASD.

Methods: We tested (1) BOL-DP-O-01-W, a whole-plant cannabis extract containing cannabidiol and Δ9-tetrahydrocannabinol at a 20:1 ratio and (2) BOL-DP-O-01, purified cannabidiol and Δ9-tetrahydrocannabinol at the same ratio. Participants (N = 150) received either placebo or cannabinoids for 12-weeks (testing efficacy) followed by a 4-week washout and predetermined cross-over for another 12 weeks to further assess tolerability. Registered primary efficacy outcome measures were improvement in behavioral problems (differences between whole-plant extract and placebo) on the Home Situation Questionnaire-ASD (HSQ-ASD) and the Clinical Global Impression-Improvement scale with disruptive behavior anchor points (CGI-I). Secondary measures were Social Responsiveness Scale (SRS-2) and Autism Parenting Stress Index (APSI).

Results: Changes in Total Scores of HSQ-ASD (primary-outcome) and APSI (secondary-outcome) did not differ among groups. Disruptive behavior on the CGI-I (co-primary outcome) was either much or very much improved in 49% on whole-plant extract (n = 45) versus 21% on placebo (n = 47; p = 0.005). Median SRS Total Score (secondary-outcome) improved by 14.9 on whole-plant extract (n = 34) versus 3.6 points after placebo (n = 36); p = 0.009). There were no treatment-related serious adverse events. Common adverse events included somnolence and decreased appetite, reported for 28% and 25% on whole-plant extract, respectively (n = 95); 23% and 21% on pure-cannabinoids (n = 93), and 8% and 15% on placebo (n = 94). Limitations Lack of pharmacokinetic data and a wide range of ages and functional levels among participants warrant caution when interpreting the results.

Conclusions: This interventional study provides evidence that BOL-DP-O-01-W and BOL-DP-O-01, administrated for 3 months, are well tolerated. Evidence for efficacy of these interventions are mixed and insufficient. Further testing of cannabinoids in ASD is recommended. Trial registration ClinicalTrials.gov: NCT02956226. Registered 06 November 2016, https://clinicaltrials.gov/ct2/show/NCT02956226.

Keywords: Autism spectrum disorder; Behavior; Cannabidiol; Cannabinoids; Child psychiatry; Clinical trials randomized controlled; Developmental disorders; Entourage effect; Neuropsychology; Tetrahydrocannabinol.

Fig. 1

Study design

Fig. 2

Trial profile: screening, randomization and treatment periods

Fig. 3

Participants (%) whose behavioral problems either much improved or very much improved on the CGI-I scale following treatment. Response to 12-week treatment using the Clinical Global Impression-Improvement (CGI-I). Positive response in this scale is defined as a rating of ‘much improved' or 'very much improved' [34]. Outcome was analyzed using Likelihood ratio chi-square test. P value is unadjusted. *Remains significant after Bonferroni-correction for multiple comparisons

Fig. 4

Impact of cannabinoid treatment on BMI. Change in BMI during 12-week treatment with either cannabinoids or placebo. a Whole-plant extract versus pure cannabinoids; b Cannabinoid treatment (either whole-plant extract or pure cannabinoids) versus placebo; c Distribution of data, bars represent 10%, 25%, Median, 75% and 90%, differences between placebo and cannabinoids were analyzed using median test; d, e Change in BMI as function of baseline level, stratified by treatment (cannabinoids or placebo) and treatment period (d first period, e second period). Correlations were analyzed using linear regression